Production of colored pictures.



* rr amen ra wrLLIAM rnANcIs FOX, or WHITESTONE, NEW YORK, .essrenon, BY- Iansnr. Assistinrnn'rs, '10 NATURAL COLOR PICTURES COMPANY, me, on NEW yore- A CQRPORAQION OF NEW YORK.

PRODUCTION or ootonnn rio'rtrnns.

insects.

No Drawing.

ous series for use in the art of cinematog raphy.

My present invention is in some respects an improvement upon that of my Patent No. 1,166,123 dated December 28, 1915, entitled Photographic process, and in other respects it may be considered as providing certain steps alternative to those described in my said patent. In the patent referred to, the steps, generally speaking, may be described as follows 1- Two negative images are first produced, one taken through a red filter and the other through a green filter, or in more general language, I produce two negative images of an object from one of which certain color sensations have been omitted and from the other of which certain other complementary color sensations have been omitted. The first mentioned image, namely, that taken through the red filter is imprinted upon transparent or translucent sensitized material and colored with a color corresponding 4 tonin to the sensations omitted from the corresponding negative, that is to say, bluish green. The second image is then imprinted upon the material in registry with the first image and colored to a color corresponding to the sensations omitted from the corresponding negative, namely, red. In the proc ess described in my said patent, the first Sp eeification of Letters Patent. Patented Felmdg, 1918. Application, filed January 13, 1917. Serial No. 142,245. I I I sitized material in a bath which simultaneously-restores the color to the firstimage and mordants the second image. The bath usedfor thispnrpose in my said patent is a solution of vanadium chlorid in oxalic-acid with potassium ferricyanidi The second image is then dyed with a basic red dye which combines with the color imparted by the, desired the mordant mentioned, to give red to the second image.

In accordance with my present invention the above method of procedure is followed with difierences which will now be pointed out. The first print, viz., that made from the red negative, is developed and instead of being toned to a blue color in a bath containing potassium ferricyanid and ferric salts, it is treated with one bath containing potassium ferricyanid and after washing, is

immersed in another bath containing the necessary ferric salts. The first bath mentioned may contain potassium ferricyanid, water and ammonia which bleaches the black silver image to white. llhe second bath ma contain ferric ammonium oxalate, water an hydrochloric acid which colors the print to the desired blue. This difiers from the process described in my patent referred to in that the potassium ferricyanid and the ferric salts are in separate baths. This is an improved proceeding because thereby I avoid precipitation which takes place when the ferric salts and potassium ferricyanid are mixed together.

The second point of improvement consists in the following: After the second print has been made it is developed and immersed in the same bleaching bath as was used for the blue image, It is then washed and immersed in a bath containing uranium nitrate with water and hydrochloric acid. The immer- 1 sion in the bleaching bath converts the black silver deposit on the sensitized material to silver ferrocyanid which reacts with the uranium contained in the second bath to form uranyl ferro-cyanid which is an orange-red color complementary to the blue of the first image. By this procedure I am enabled t6 obtain excellent results with less operations and in less time than in the pro-' cedure described in my patent referred to in the red color produced a more vivid crimson used for obtaining the red color. It is some-' times found advisable to mix a solution of some basic red or other color dye with the uranium solution, the uranium acting as a mordant for the red dye as it is precipitated in the film. This is not absolutely necessary but the addition of the basic red dye makes than in the case in which the uranium solution is used without the basic dye. Like- 'w1se,'basic orange or yellow dyes may be usgd to give a more vivid orange or yellow re By this method I am enabled to color prints a very desirable red and this step of my process is of wide applicability. Uranium toning has been previously proposed but has not been of practical value, so far as I am aware, because of the uncertain results that were attained. It may be stated briefly that uranium is a radio-active material and is affected by light, so that consistent results with the same have been diflicult of attainment. In the method described herein, however, in which the potassium ferricyanid and the uranium salts are used in separate baths and the procedure and proportions hereinafter more fully described are employed, ex-

consisting in reproducing instraight line sequence all of the images taken through cellent and uniform results are obtained.

. The details of the procedure described may now be given somewhat more fully. v The first step in the process comprises pro duclng a suitaolenegative. A series of pietures is taken by means of a camera employing'a red and green colored filter, the images being taken alternately through the red and green portions of the filter. This negative is made upon suitable'transparent or translucent material; such, for example, as'pyroxylene stock coated with silver bromid emulsion and extra sensitized to be panchromatic. The negative strip is then developed, fixed, washed and dried in well known manner.

A positive is then made, the first step the red filter. The print thus made is upon transparent or translucent film-stock coated with silver bromid emulsion, not necessarily panchromatic, the sensitized emulsion preferably being upon but one side of the stock. After the development of this print from the red negative the same may either be Potassium ferricyanid 1 lb. Water 10 lbs. Ammonia (.880) 8 ounces.

This will bleach the black silver image to a. white, which takes from three to five minfaintly visible. noted in my patent referred to above. and

utes. It is then Washed to remove the 'bleacher, and immersed in another bath containing Ferric ammonium oxalate llb. Water l0 lbs. Hydrochloric'acid 4ounces.

The image is then fixed in a sodium thiosulfate solution, is again washed, dried and is ready 'for the application of the second print. This has toned theimage a rich transparent blue color.

The positive strip may now be given a second coating of emulsion, the operation being performed at such a temperature that the second coating will in practical efiect combine-with the first coating to make essentially but a single homogeneous coating uponthe underlying film stock. I may also proceed, if desired, without recoating the stock. Assuming that the film'is re-coated, the next step consists in impressing upon the positive strip and in precise superposition upon the image already there, the image of the green negative, that is, the negative taken through the green filter. After this green image has been printed upon the positive, the positive strip is developed and is either fixed or left unfixed, as desired. The positivestrip is then immersed in the same bleaching bath as was usedfor the blue image, namely, the bath consist-.

Uranium nitrate 8 oz. Water 10 lbs. Hydrochloric acid 4 ounces.

The strip is left in this bath for approximately five minutes, after which it is fixed, and washed for half an hour when it is ready, for drying and projecting in a moving picture projecting machine.

The'development of the second image results in a bleaching-out and entire obliteration of the bluish green color from the first image, although the image itself remains This is the same effect as this effect ensues because the first image impressed upon the positive film is open to the action of any solution which may be used in the treatment of the second image, no attempt being made to protect the same. This color is restored to the first image, by the acid in the uranium nitrate and hydrochloric acid bath. this bath being sufficiently acid to restore the color to the first image. The immersion of the film in the potassium ferricyanid bath after the second print has been developed, converts the black silver ,de-

nasaa'm posit of the'second print to silver ferrocyanid and the reaction in the second bath with the uranium contained therein forms a substance which is apparently .uranyl ferro-cyanid, and which is an orange red color complementary to the blue of the first image. s

In many cases it is advisable to mix a solution of some basic red dye with the uranium nitrate solution, the uranium acting as a mordant for the red dye as it is precipitated in the film. A strength-of dye of about .001 per cent. is employed and the dye used may be of any of the basic dyes mentioned in my patent above referred to or other suitable basic dyes. The dye may be used as stated when it is deemed advisable to have a red of a more vivid color than is produced by the uranium bath without the basic dye.

As stated, the second rint may be superposed upon the first without firstre-coating the film in the same manner as is described in my patent above. referred to. If but a I single coating of emulsion on the positive film stock is to be employed, the film, after the development of the first printing should be immersed in a combined Washing bath containing, however, a small percentage such as one per center acetic acid, this operation being carried out in the dark room and-being intended to wash out surplus de-' veloping solution and to arrest the process or development. When the first image is printed upon the positive strip, in this case care should be takenthat the exposure be not so great as. to affect the entire mass of the sensitive -"coating. Therefore the first image will in efiect be portrayed in the upper layer of the coating, the emulsion underlying it remaining sensitive and it. is this sensitive portion of the emulsion which is utilized in impressing the second print upon the positive strip, this operation not being interfered with by the image already there,

which has been turned a bluish green and therefore obstructs the passage of light but little, if at all.

It should be particularly noted that I am enabled by the processes outlined, to obtain results with the uranium toning operation which are uniformly excellent, such results being obtained, however, only as a result of a long period of experimentation. If a basic red dye is additionally used, suitable dyes will include rhodamin azin red, acridin red and safi'ranin red. It a vivid shade of red difi'erent from crimson is desired, other suitable dyes, such as basic orange or basic yellow dyes, may be used.

Having now described my invention, what I claim and desire to secure by Letters Pat-j ent is 1. A photographic process comprising,

imprinting a negative image of an object,

' printed thereon,

thereon, developing said. second image, im-

mersing the material in a bleaching bath containing potassium ferricyanid, washing,

and immersing in a bath containing uramum nitrate and hydrochlo ric.acid and fixing and Washing the second image, substantially s described.

2. A photographic process comprising, imprinting a negative image of an object, from which certain color sensations have been omitted, upon light-transmissive sensi ,ti'zed material, developing, bleaching the print in a bath containing potassium ferricyanid' and ammonia, washing, toning the print in a bath containing ferrlc-am'momum oxalate and hydrochloric acid, fixing, washing, imprinting a second image of the same object, from which other color sensations have been omitted, upon said. material in registry with the first image imprinted thereon, developing said second image and thereby decoloring said first image; and simultaneously restoring color to said first image and coloring said second image red, substantially as described.

'3. A photographic process comprising, imprinting a negative image of an object, from which certain color sensations have been omitted, upon light-transmissive sensitized material, developing, bleaching the print in a bath consisting of potasslum ferricyanid and ammonia, washing, toning the print in a bath containing ferric ammonium oxalate and hydrochlori acid, fixing, washing, imprinting a second unage of the same object, from which other color sensations have been omitted, upon said material in registry with the first image 1mdeveloping said second image, immersing the material in a bleaching bath similar to that used for the first print, washing. immersing in a. bath containinghydrochloric acid and a uranium salt adapted to form uranium chlorid with the acid, and fixing the second image, substantially as described.

a. A photographic process comprising, imprinting a negative image of an object, from which certain color sensations have been omitted, upon light-transmissive sensi- -'tized material, developing, bleaching the object, from which other color sensations have been omitted, upon said material in registry with the first image imprinted thereon, developing said second image, and coloring said second image red by means of potassium ferricyanid and a uranium salt in solution, substantially as described.

5. A photographic process comprising, imprinting a negative lmage of an object, from which certain color sensations have been omitted, upon light-transmissive sensitized material, coloring said image bluishgreen, imprinting a second image of the same object, from which other color sensations have been omitted, upon said material in registry With the first image imprinted thereon, developing said second image, immersing the material in a bleaching bath containing potassium ferricyanid, Washing, and innnersing in a bath containing uranium nitrate, hydrochloric acid and a basic dye, fixing and. Washing, substantially as described.

This specification signed and witnessed this 9th day of January, 1917.

WILLIAM FRANCIS FOX.

Y Witnesses:

- DYER SMITH, I. MCINTOSH. 

